![ELI5: How is Palladium able to cram all its electrons into it's first 4 valence shells, but the elements both above AND below it are forced to use their 5th shell? : ELI5: How is Palladium able to cram all its electrons into it's first 4 valence shells, but the elements both above AND below it are forced to use their 5th shell? :](https://external-preview.redd.it/7wPcIZfACSejBLD7haCQxLkUsmlxts3gJscWRY2vMWw.jpg?auto=webp&s=073e556447856ed98ab0c80f0fad358979ffcb47)
ELI5: How is Palladium able to cram all its electrons into it's first 4 valence shells, but the elements both above AND below it are forced to use their 5th shell? :
![Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to palladium Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to palladium](https://www.nanowerk.com/nanotechnology-news/id37886.jpg)
Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to palladium
![The value of n (i.e. principal quantum number) for the valence shell of palladium is (atomic number-40) The value of n (i.e. principal quantum number) for the valence shell of palladium is (atomic number-40)](https://d10lpgp6xz60nq.cloudfront.net/web-thumb/32522605_web.png)
The value of n (i.e. principal quantum number) for the valence shell of palladium is (atomic number-40)
![Valence band XPS of (a) CeO 2 and TiO 2 (b) Pt, Pd, and Rh metals and... | Download Scientific Diagram Valence band XPS of (a) CeO 2 and TiO 2 (b) Pt, Pd, and Rh metals and... | Download Scientific Diagram](https://www.researchgate.net/publication/233532567/figure/fig4/AS:650033267474488@1531991416619/Valence-band-XPS-of-a-CeO-2-and-TiO-2-b-Pt-Pd-and-Rh-metals-and-c-PdO-and-the.png)
Valence band XPS of (a) CeO 2 and TiO 2 (b) Pt, Pd, and Rh metals and... | Download Scientific Diagram
![Modulating the oxidative active species by regulating the valence of palladium cocatalyst in photocatalytic degradation of ciprofloxacin - ScienceDirect Modulating the oxidative active species by regulating the valence of palladium cocatalyst in photocatalytic degradation of ciprofloxacin - ScienceDirect](https://ars.els-cdn.com/content/image/1-s2.0-S0926337322000327-ga1.jpg)